Effects of anthropogenic electromagnetic fields used for subsurface oil and gas exploration (controlled-source electromagnetics, CSEM) on the early development of Atlantic haddock

Overview

Controlled source electromagnetics (CSEM) uses electromagnetic fields (EMF) to detect oil reservoirs. The Atlantic haddock (Melanogrammus aeglefinus), a commercially important demersal fish species, may be affected by such EMF surveys due to overlap with its egg distribution areas.

Study Design

• Haddock eggs were exposed to EMF replicating CSEM survey conditions in a laboratory.
• Three different EMF intensities simulated various distances from the EMF source to the organism.
• Exposure lasted for 15 minutes, with an additional worst-case scenario of 1-hour exposure at the highest EMF level.

Findings

• No malformations, mortality, or effects on hatching were observed in any treatment group.
• EMF exposure induced tachycardia (increased heart rate) in newly hatched larvae.
• There was a reduction in the size of the yolk sac reserve in exposed larvae.
• These effects were significant even at the lowest tested EMF intensity (equivalent to 1000 m distance from the source) and intensified with greater exposure time and higher EMF intensity.

Conclusion

The study demonstrates that EMF exposure from CSEM surveys can negatively impact the physiology of early-life stages of Atlantic haddock, particularly by inducing tachycardia and reducing yolk sac reserves. These health effects are present even at low levels of EMF exposure and can intensify with greater exposure, highlighting a clear connection between electromagnetic field exposure and adverse developmental outcomes in marine species.